The invention relates generally to the field of propulsion systems. In particular, the invention concerns an on-board fuel cell system for mobile vehicles such as trains, marine vessels, automobiles and other mobile means of transportation.
As concerns surrounding traditional power sources persist, investigation into alternative means of power generation are becoming increasingly important. In particular, environmental and political concerns associated with combustion-based energy systems cannot be ignored. In an effort to reduce dependence on these types of power supplies and methods, interest is increasing in devices capable of generating electricity by consuming fuels without requiring combustion.
In addition to being utilized for the generation of electricity, however, combustion processes are most commonly used to power means of transportation such automobiles, trains, or marine vessels. Motor vehicles alone are among the chief contributors to pollution problems associated with combustion of fuel. So, while alternative power sources such as nuclear and hydroelectric systems may be suitable for large scale electric utilities, they do not present an ideal solution to the problems associated with powering means of transportation such as motor vehicles.
Alternatives to internal combustion engine powered motor vehicles have included various types of electric vehicles. Electric vehicles are well known in the art. Typical electric vehicles are powered by nickel-cadmium batteries which drive electric motors of anywhere from twenty to 100 horsepower. The batteries are generally rechargeable by stationary direct current (dc) power supplies. A problem with known systems, however, is that they require constant recharging and offer limited range between required recharging stops.
Known systems are also expensive. Solar rechargeable systems, such as are available from Solectria of Arlington, Mass., represent one attempt to increase the travel range and control the cost of electric motor vehicles. Drawbacks associated with the solar generation of electricity, however, include its usefulness being limited to clear weather and daylight hours, and the expense of the vehicle.
Fuel cells, therefore, have been explored as a means for powering electric vehicles and reducing the constant need to recharge the vehicle from off-board sources. Fuel cells electrochemically convert fuel, such as hydrocarbon fuel, to electricity. Typically, a combustion reaction is not involved.
A drawback associated with prior art fuel cell systems, however, is that they are not economically viable for applications in which the power rating of the fuel cell must meet propulsion demands. In motor vehicle applications, for example, a fuel cell system designed to provide sufficient power required by the vehicle for cruising, let alone for peak surge, would be prohibitively expensive. While various known systems have attempted to exploit the advantages of designating a surge battery to meet peak demand in motor vehicle applications, none has satisfactorily overcome the economic problems.
It is an object of the invention, therefore, to provide a system for powering a motor vehicle which does not require a combustion reaction.
It is another object of the invention to provide such a system which has a range comparable with that of traditional combustion engines without requiring interruptive recharging from off-board sources.
It is still another object of the invention to provide an economically feasible system for powering a motor vehicle which can accommodate typical motor vehicle surge and range demands.
It is yet another object of the invention to provide a fuel-cell powered vehicle that is capable of generating power for off-board consumption.
Other general and more specific objects of the invention will in part be obvious and will in part appear from the drawings and description which follow.